Seals of the general type involved herein are classified in class 288. For example, see U.S. Pat. No. 2,934,368 which discloses relevant prior art.
In a seal having a sealing lip under a compressive load only when mounted in an operative sealing position, the spring is deformed from a circular cross section to an elliptical cross section. The design of the groove in which the spring is mounted has heretofore provided space to accommodate the elliptical cross section of the spring. For example, see FIGS. 7 and 8 of said Pat. No. 2,934,368 wherein a straight line across the apex of lips 33 passes substantially above the centerline of spring 37. When the lips are compressed into sealing contact with the members to be sealed, a downward component of force is exerted on spring 37 tending to push it to the bottom of the groove, thereby reducing the effectiveness of said spring. The present invention solves that problem.
This invention is directed to an annular seal of resilient elastomeric material. The body of the seal is provided with an axially directed groove containing a spring between two interconnected body portions. At least one of the body portions has a sealing lip projecting in a radial direction and being generally opposite the location of said spring. The groove has arcuate portions spaced from the bottom of the groove and such arcuate portions are in embracing contact with opposite surfaces of the spring.
The groove bottom is a portion of an ellipse and has embracing contact with a juxtaposed portion of the spring only when the spring and sealing lip are under a compressive load. The spring and lip are placed under a compressive load only when the seal is mounted in an operative sealing position with the surface to be sealed.
It is an object of the present invention to provide an annular seal constructed and arranged to maximize effectiveness of a spring when a sealing lip is placed under a compressive load.
It is another object of the present invention to provide an annular seal wherein a spring between two body portions at least one of which has a sealing lip bottoms out against an elliptical portion of the grooves containing the spring when the sealing lips are placed under a compressive load.
Other objects will appear hereinafter.